思路

根据子集的定义可以得到符合条件的子集应该是在树枝节点和叶子节点上都需要收集结果

代码

class Solution {
public:vector<int> path;vector<  vector<int> > result;void backtracking(vector<int> nums, int startIndex){result.push_back(path);for(int i = startIndex; i < nums.size(); i++){path.push_back(nums[i]);backtracking(nums, i+1);path.pop_back();}return;}vector<vector<int>> subsets(vector<int>& nums) {result.clear();path.clear();backtracking(nums, 0);return result;}
};